Collapsible reflector

ABSTRACT

A collapsible dished paraboloid reflector having an array of petals that surround and have petals that are rotatably connected at their inner ends to a reflector hub. The array of petals comprises a series of substantially spear tip shaped or lanceolate shaped petals that alternate between semi-hour glass shaped petals. Substantially wedge shaped petals are located between and have lateral edges that are rotatably connected in edge to edge relationship to each lanceolate shaped petal and semi-hour glass shaped petal. The edges of the petals when viewed from the focal point of the fully deployed reflector substantially approximates the parabolic radial curvature of the fully deployed reflector. The lanceolate shaped petals and the semi-hour glass shaped petals are of rigid construction lengthwise so that they are not capable of flexing in a lengthwise direction whereas the wedge shaped petals are of relatively flexible construction lengthwise so that they are capable of flexing lengthwise as the reflector assembly is being deployed or collapsed. The construction of the collapsible reflector permits it to be collapsed into a compact package and permits the reflector to be deployed to present a dished rigid paraboloid shaped surface.

United States Patent Hoyer 51 Oct. 17, 1972 [54] COLLAPSIBLE REFLECTOR[72] Inventor: Sigurd Hoyer, Rockville, Md.

[73] Assignee: Fairchild Industries, Inc.

[22] Filed: July 7, 1970 [21] Appl. No.: 52,890

Primary Examiner'-T. H. Tubbesing Attorney-Michael W. York [57] ABSTRACTA collapsible dished paraboloid reflector having an array of petals thatsurround and have petals that are rotatably connected at their innerends to a reflector hub. The array of petals comprises a series ofsubstantially spear tip shaped or lanceolate shaped petals thatalternate between semi-hour glass shaped petals. Substantially wedgeshaped petals are located between and have lateral edges that arerotatably connected in edge to edge relationship to each lanceolateshaped petal and semi-hour glass shaped petal. The edges of the petalswhen viewed from the focal point of the fully deployed reflectorsubstantially approximates the parabolic radial curvature of the fullydeployed reflector. The lanceolate shaped petals and the semi-hour glassshaped petals are of rigid construction lengthwise so that they are notcapable of flexing in a lengthwise direction whereas the wedge shapedpetals are of relatively flexible construction lengthwise so that theyare capable of flexing lengthwise as the reflector assembly is beingdeployed or collapsed. The construction of the collapsible reflectorpermits it to be collapsed into a compact package and permits thereflector to be deployed to present a dished rigid paraboloid shapedsurface.

10 Claims, 16 Drawing Figures PATENTEDHBI 17 m2 SHEET 2 0F 4 INVENTOR.lo Foyer PATENTEDnm 11 I972 SHEET 3 [If 4 COLLAPSIBLE REFLECTORBACKGROUND OF THE INVENTION Collapsible reflectors have many uses.Collapsible reflectors are generally small in size in their collapsedstate compared to their size when fully deployed. This ability to becollapsed into a small size allows collapsible reflectors to be employedin many situations where the use of corresponding rigid reflectors wouldbe impossible. Collapsible reflectors have been used in situations whereit was necessary to transport the reflector in a small container such asthe type that are required to transport and place a reflector in space.Collapsible reflectors can also be used with or without containers ontrucks, trailers, and other vehicles and they can also be used onwatercraft.

Although there are many uses for collapsible reflectors and there havebeen numerous prior designs, most prior art reflectors have severaldisadvantages that limit their use. Many prior art reflectors,particularly those for use in space, lack sufficient rigidity to becapable of being folded back up once they have been fully deployed.Another serious disadvantage that many previous reflector designspossess is a lack of rigidity in the deployed state. This lack ofrigidity has in part been due to a comparatively low percentage of fixedor rigid structure in the reflector. This low percentage of rigidstructure was required in prior designs to permit collapsing of thereflector. This lack of rigidity can result in distortions of the shapeof the reflector when it is deployed which could result in a loss in theperformance and reliability of the reflectors. This lack of rigidity hasmore serious consequences in the case of large reflectors that aredesigned for use in space. With collapsible reflectors that are to beused in space, it is highly desirable from the standpoint of economy andreliability to test the performance of the reflector in its deployedcondition prior to sending it into space. Unfortunately, previous largesurface reflectors designed to retain their geometric configuration inthe zero gravity environment of space will not retain their shape whensubjected to gravitational forces on earth. This has previouslyprevented proper performance and reliability testing of largecollapsible reflectors prior to placing them in space.

SUMMARY OF THE INVENTION This invention relates to collapsiblereflectors and more particularly to a collapsible reflector that has arigid dished reflective surface when it is fully deployed.

It is accordingly an object of the present invention to provide acollapsible reflector that is capable of presenting a dished reflectivesurface that possesses a high degree of rigidity and resists distortionwhen the reflector is fully deployed.

It is an object of the present invention to provide a collapsiblereflector that is capable of being collapsed into a compact package.

It is an object of the present invention to provide a collapsiblereflector that is easy to collapse and deploy.

It is also an object of the present invention to provide a collapsiblereflector that is capable of presenting a large reflective surface whenthe collapsible reflector is fully deployed.

The present invention provides a collapsible and deployable reflectorhaving a plurality of petals surrounding a hub. The petals are adaptedto present'a dished substantially symmetrical reflective surface upondeployment of the reflector and they have lateral edges that have acurvature when viewed from the focus of the deployed reflector thatsubstantially approximates the radial curvature of the surface of thepetals of the fully deployed reflector. Interconnecting means areprovided that are connected to the lateral adjacent edges of the petalsfor pivotally connecting the petals together in edge to edgerelationship and means are connected to the hub and at least some of thepetals for pivotally connecting the petals to the hub.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be hereinafter morefully described with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of the collapsible reflector of thisinvention in the fully deployed state;

FIG. 2 is a perspective view of the collapsible reflector illustrated inFIG. 1 illustrating the reflector as the reflector is undergoingdeployment or is in the process of being collapsed;

FIG. 3 is a perspective view of the collapsible reflector illustrated inFIGS. 1 and 2 when the reflector is in the fully collapsed state;

FIG. 4 is a plan view of part of the fully deployed collapsiblereflector illustrated in FIG. 1;

FIG. 5 is a cross sectional view of part of the fully deployedcollapsible reflector taken on the line 5-5 of FIG. 4;

FIG. 6 is a view of a portion of the structure illus trated in FIG. 5showing the edge of the reflector;

FIG. 7 is an enlarged view of part of the deployable reflectorillustrated in FIG. 4 with certain parts broken away to illustrate theinterior construction of the reflector;

FIG. 8 is a sectional view of a lanceolate shaped petal taken on theline 8-8 of FIG. 7;

FIG. 9 is a sectional view of a lanceolate shaped petal taken on theline 9-9 of FIG. 7;

FIG. 10 is a sectional view of a wedge shaped petal taken on the line10-10 of FIG. 7;

FIG. 11 is a sectional view of a wedge shaped petal taken on the line11-11 of FIG. 7;

FIG. 12 is a sectional view of a semi-hour glass shaped petal taken onthe line l2--l2 of FIG. 7;

FIG. 13 is a sectional view of a semi-hour glass shaped petal taken onthe line 13-13 in FIG. 7;

FIG. 14 is an enlarged view of part of the collapsible reflectorillustrated in FIG. 2;

FIG. 15 is a sectional view taken on the line l5 15 of FIG. 14; and

FIG. 16 is a perspective view of the interconnecting means that can beutilized with the collapsible reflector of this invention.

DETAILED DESCRIPTION OF TI-IE PREFERRED EMBODIMENT Referring first toFIG. 1 the collapsible reflector 10 of the invention is illustrated inits fully open or deployed configuration. The reflector 10 comprises anarray or plurality of substantially spear tiped shaped or lanceolateshaped petals 11 that come to a point at each end that are locatedaround and are pivotally mounted on a centrally located hub 12 by meansof mounting struts 13 that are rigidly connected to the outer peripheryof the hub and whose outer ends are pinned to the inner ends of thelanceolate shaped petals so that the lanceolate shaped petals are freeto rotate in an upward direction about the pins as will be describedhereinafter in greater detail. The reflector also comprises an array orplurality of semi-hour glass shaped petals 14 that are locatedalternately between the lanceolate shaped petals 11 and are locatedaround and pivotally mounted on the centrally located hub 12 by means ofthe mounting struts 13 that are rigidly connected to the outer peripheryof the hub and whose outer ends are pinned to the inner ends of the hourglass shaped petals in a manner similar to that for the lanceolateshaped petals. The reflector assembly 10 also comprises an array orplurality of substantially wedge shaped petals that are located aroundthe centrally located hub 12 and between each lanceolate shaped petal 11 and the hour glass shaped petal 14. The hour glass shaped petals 14are pivotally connected to the adjacent wedge shaped petals 15 byinterconnecting means 16 that comprise hinge members that are connectedto the lateral adjacent edges of the hour glass shaped and wedge shapedpetals. The lanceolate shaped petals 11 are pivotally connected to theadjacent wedge shaped petals 15 by similar interconnecting means 16 thatcomprise hinge members that are connected to the lateral adjacent edgesof the lanceolate shaped petals and the wedge shaped petals on theunderside of the reflector 10, as illustrated in FIG. 2. The uppersurfaces of the lanceolate shaped petals 11, hour glass shaped petals14, and the wedge shaped petals 15 are appropriately compound curved ordished slightly so that the fully deployed reflector 10 presents areflector having a dished paraboloid that is substantially symetricalabout its axis that passes through the center of the hub 12 and thefocus of the paraboloid that is suitable for use in reflectingelectromagnetic radiation.

In FIG. 2 the reflector 10 is illustrated in its partially collapsed orpartially open configuration. As illustrated in FIG. 2 the lanceolateshaped petals 11 are shown as being rotated upward and inward about thehub 12 from their positions indicated in FIG. 1 due to the movement ofactuating members or arms 17 that form part of a hydraulic activatingunit 18 that is connected to the underside of the hub and whose outerends are rotatably connected to the lower end of support trusses 19 thatare rigidly secured to the back side of the lanceolate shaped petalsalong the central axis of the lanceolate shaped petals. The hour glassshaped petals 14 are also shown as being rotated upward and inward aboutthe hub 12 from their positions indicated in FIG. 1 due to the action ofother activating members or arms 17 that form part of the hydraulicactivating unit 18 and whose upper ends are pivotally connected to thelower ends of support trusses 19 that are rigidly connected to the backof the hour glass petals along the central axis of the hour glasspetals. The wedge shaped petals 15 that are located between andpivotally connected in edge to edge relationship to the adjacent lateraledges of the lanceolate shaped petals 11 and the hour glass shapedpetals 14 by the hinge members 16 on the upper and lower sides of thereflector have pivoted about the edges of the lanceolate shaped and hourglass shaped petals when the reflector assembly is in its partially openor partially closed configuration. It should be noted that when thereflector assembly 10 is in its partially open or partially closedconfiguration the lanceolate shaped petals 11 are located toward thecenter of the assembly whereas the hour glass shaped petals 14 arelocated on the exterior of the assembly and the hydraulic unit 18 mustbe properly programmed to accomplish this to insure proper operation ofthe reflector assembly when the assembly is being closed or undergoingdeployment.

The fully collapsed reflector assembly 10 is illustrated in FIG. 3. InFIG. 3 it can be seen that the hour glass shaped petals 14 have beenrotated upwardly and inwardly by the action of the activating members 17of the hydraulic activating unit 18 so that they are located on theexterior of the assembly 10. The lanceolate shaped petals 11 have alsobeen rotated upwardly and inwardly by the action of the activatingmembers 17 of the hydraulic activating unit 18 so that they are locatedin the interior of the collapsed assembly 10. The wedge shaped petals 15have been forced to pivot towards each other about the lateral edges ofthe lanceolate shaped petals and the hour glass petals 14. Since thewedge shaped petals 15 have pivoted towards each other and thelanceolate shaped petals 1 l have pivoted upwardly and inwardly so thatthey are located on the interior of the assembly and since the hourglass shaped petals have pivoted upwardly and inwardly so that they arelocated on the exterior of the assembly, the reflector 10 forms a verycompact package when it is in its collapsed state.

As indicated in FIGS. 4 through 6 the curvature A of the lateral edgesof the lanceolate shaped petals 11, the curvature B of the lateral edgesof the semi-hour glass shaped petals 14, and the curvature C of thelateral edges of the wedge shaped petals 15 when viewed from the focusor focal point F of the fully deployed reflector must substantiallyapproximate the radial curvature D of the surface of the fully deployedreflector when it is viewed in cross section as illustrated in FIG. 5.In view of this requirement related to the curvature of the lateraledges of the various petals, if a lanceolate shaped petal 11 is rotatedabout its long axis when in the fully deployed state and its lateraledge is placed against the corresponding surface of the fully deployedreflector the edge A will substantially conform to the curvature D asillustrated in FIG. 6. In a similar manner if the hour glass shapedpetal 14 or the wedge shaped petal 15 is rotated 90 about its long axiswhen in the fully deployed configuration and if their lateral edges wereplaced against the corresponding surface of a cross section of the fullydeployed reflector 10, the edges B and C would substantially conform tothe curvature D as illustrated in FIG. 6. This requirement related tothe curvature of the petals is important since this permits thereflector to possess comparatively rigid petals that provide a ratherlarge relatively rigid paraboloid reflective surface in the fullydeployed state and yet be capable of being folded into a very compactpackage. In order to appreciate the importance of the curvature of theedges of the petals reference should first be made to FIG. 1 thatillustrates the fully deployed reflector 10. From FIG. 1 it is apparentthat a solid paraboloid is capable of being cut into a series oflanceolate shaped petals 11, wedge shaped petals 15 and semi-hour glassshaped petals 14 around a central hub 12 in the manner illustrated. Itis also apparent that if the lateral edges of these petals are flexiblyor rotatably connected the petals can be folded inwardly as illustratedin FIG. 3 so that one edge of each wedge shaped petal 15 is pointingtoward the center of the collapsed and the wedge shaped petals formsubstantially 90 angles with the attached lanceolate shaped petals 11and hour glass shaped petals 14 and thus the reflector 10 forms a verycompact assembly in the collapsed configuration. If the edges of thepetals did not substantially correspond to the curvature D of thedeployed reflector assembly then the wedge shaped petals could not formthe 90 relationships with the lanceolate shaped petals 11 and the hourglass shaped petals 14 since these petals are connected and when thewedge shaped petals are rotated into the 90 relationship their edgesmust conform to the radial curvature of the reflector that the hourglass shaped petals and the lanceolate shaped petals possess sincebinding between the petals or a separation or distortion of the petalswould otherwise tend to occur.

The means for mounting the lanceolate shaped petals 11 and the hourglass shaped petals 14 to the hub 12 are illustrated in greater detailin FIG. 5. The mounting means comprises the strut 13 whose inner end isrigidly connected to the outer edge of the dish shaped hub 12 and whoseouter end is connected to the lower end of the lanceolate shaped petal11 by means of the pin 20 so that the lanceolate shaped petal is free torotate in an upward direction. It should be noted that the hub 12 isdished so that it forms a curvature E when seen in cross section that isan extension of the radial parabolic curvature D of the rest of thedeployed reflector 10. It can also be seen that the activating member orarm 17 of the activating unit 18 extends outward from the activatingunit and has an outer end that is pivotally connected to the lower endof the truss member 19 by means of the pin 21. The truss 19 is of rigidconstruction and has an upper tubular strut 22 that is bent to conformto the curvature D of the underside of the lanceolate shaped petal 11which when viewed in cross section has substantially the same curvatureas the upper surface D. The upper tubular strut 22 is rigidly connectedto a lower tubular strut 23 by means of tubular cross or connectingstruts 24, 25, 26, 27, 28 and 29, and these cross struts are reinforcedby the diagonal tubular struts 30, 31, 32, 33 and 34 whose ends arerespectively connected to the junctions of the upper strut 22 and thestrut 24, the lower strut 23 and the strut 25; the lower strut 23 andthe strut 25; the upper strut 22 and the strut 26; the upper strut 22and the strut 26; the lower strut 23 and the strut 27; the lower strut23 and the strut 27; the upper strut 22 and the strut 28; the upperstrut 22 and the strut 28; and the lower strut 23 and the strut 29. Thesame type of truss construction is used for the trusses 19 thatreinforce the hour glass petals 14.

The construction of the lanceolate shaped petals 11, the hour glassshaped petals l4 and the wedge shaped petals are illustrated in greaterdetail in FIGS. 7 through 13. In FIG. 7 a portion of the fully deployedreflector assembly is illustrated with the major portion of a wire meshelectromagnetically reflective screen covering 35 removed so that theinternal construction of the lanceolate shaped petals 11, the hour glassshaped petals l4 and the wedge shaped petals 15 is clearly visible. Thelanceolate shaped petal 11 comprises two frame members or struts 36 thatare joined at their ends and are curved so that their outer edges givethe required curvature A when viewed from the focal point of the fullydeployed reflector. These struts are reinforced in a radial direction bya reinforcing member or strut 37 that extends along the long centralaxis of the lanceolate shaped petal and whose ends are joined to thejunction of the ends of the frame members 36. Reinforcing struts 38, 39and 40 extend outwardly in a direction transverse to the long axis ofthe reinforcing strut 37 and they are connected to the reinforcing strutand the frame struts 36. A groove 41 is provided in the lower junctionof the frame members 36 that is designed to accept the outer end of oneof the mounting struts 13. The hour glass shaped petal 14 comprises twoframe members or struts 42 that are curved so that their outer edgesgive the required curvature B when viewed from the focal point of thefully deployed reflector assembly 10. These frame members 42 areconnected at their outer ends by an outer frame member 43 that isslightly curved in an outward direction so that it can form part of therim of the fully deployed reflector 10. The frame members 42 areconnected at their inner ends by an inner frame member or strut 44 thatis curved outwardly slightly. This inner frame member 44 has a slot 45that is designed to accommodate the outer end of a mounting strut 13.Located along the central axis of the hour glass shaped petal 14 is aradial reinforcing member or strut 46 whose ends are connected to thecenter of the outer frame member 43 and the inner frame member 44.Reinforcing struts 47, 48 and 49 are located in a direction generallytransverse to the long axis of the reinforcing member 46 and the ends ofthese struts are connected to the reinforcing member and the framemembers 42.

The wedge shaped petal comprises two outer frame members or struts 50that are connected together at their inner ends to form a point and areconnected at their outer ends by a frame member or strut 51 that isslightly curved in an outward direction so that it can form part of therim of the fully deployed reflector assembly 10. The outer frame members50 are curved so that their outer edges give the required curvature Cwhen viewed from the focal point of the fully deployed reflector.Reinforcing members or struts 52, S3 and 54 extend across the width ofthe wedge shaped petal and their ends are connected to outer framemembers 50. The wedge shaped petal 15 has no radial reinforcing strutsuch as the radial reinforcing strut 37 of the lanceolate shaped petal11 and the radial reinforcing strut 46 of the hour glass shaped petal 14and consequently the wedge shaped petal is comparatively flexible in alengthwise direction whereas the lanceolate shaped petals and the hourglass petals are of substantially rigid lengthwise construction and arenot flexible in the lengthwise direction in view of their reinforcingstruts.

As illustrated in FIGS. 8 and 9 the reinforcing member 37 of thelanceolate shaped petal 11 is of substantially uniform thicknessthroughout its length and is curved so that its upper surfacecorresponds to the curvature D and its lower surface corresponds to thecurvature D when viewed from the side. The truss 19 is connected to thelower surface of the reinforcing member 37 to give the supporting memberadditional strength and to prevent it from flexing. It can also be seenthat the upper surfaces of the reinforcing struts 38, 39 and 40 arecurved inward or dished so that the lanceolate shaped petal 11 can formpart of a paraboloid when the reflector assembly is fully deployed. InFIG. 9 as indicated for one of the reinforcing struts 39, thereinforcing struts 38, 39 and 40 are thinner at G near the reinforcingmember 37 than they are at H near the frame member 36 and thus thereinforcing struts 38, 39 and 40 can bend or flex and this permits thelanceolate shaped petal 11 to bend elastically slightly up and down in adirection that is transverse to the long axis of the reinforcing member37 as indicated by the broken lines and the arrows.

The outer frame member 50, the reinforcing struts 52, 53 and 54, and theframe member 51 of the wedge shaped petal 15 are also dished or curvedas illustrated in FIGS. 10 and 11 so that when the wedge shaped petal iscovered with wire mesh and viewed in section from the side it has acurvature D and the surface of the wedge shaped petal can form a part ofa parabolic shaped surface of the reflector assembly 10 when thereflector assembly is fully deployed. It should be noted, however. thatsince the wedge shaped petal has no radial reinforcing member such asthat at 37 in FIG. 8, the wedge shaped petal is free to flex asindicated by the arrows and the broken lines so that the underside ofthe petal when viewed in cross section from the side it presents theinverted curvature indicated by D" and the dotted lines that issubstantially equivalent to the curvature D. As illustrated for thereinforcing member 53 in FIG. 11 the reinforcing members 52, 53 and 54and the frame member 51 are substantially of uniform thicknessthroughout their lengths so that they will not tend to bend in themanner described previously for the leaf shaped petal and thus the wedgeshaped petal is resistant to bending in a direction transverse to itslong axis.

As illustrated in FIGS. 12 and 13 the frame members 42, the reinforcingmember 46, the reinforcing struts 47, 48, 49, the outer frame member 43and the inner frame member 44 of the hour glass shaped petal 14 aredished or curved so that when the hour glass petal is viewed in crosssection from the side it has a curvature D and the surface of the hourglass shaped petal can form a part of a parabolic shaped surface of thereflector assembly when the reflector assembly is fully deployed. Theunderside of the reinforcing member 46 is also connected to the truss 19to give the reinforcing member additional strength and to prevent itfrom flexmg.

In FIG. 13 as indicated for one of the reinforcing struts 48, the innerframe member 44, the reinforcing struts 47, 48 and 49 and the outerframe member 43 are thinner at I near the reinforcing member 46 thanthey are at .I near the frame member 42 and thus the inner frame member44, the reinforcing struts 47, 48 and 49 and the outer frame member 43can bend or flex and this permits the hour glass shaped petal 14 to bendelastically slightly up and down in a direction that is transverse tothe long axis of the reinforcing member 46 as indicated by the brokenlines and the arrows.

The various frame members and reinforcing struts of the lanceolateshaped petals 11, the semi-hour glass shaped petals 14 and the wedgeshaped petals 15 may be constructed from various types of honeycombmaterials that are familiar to those skilled in the art. It will also beappreciated that various types of wire mesh screen coverings and thatreflect electromagnetic radiation that are familiar in the art can beused to cover the semi-hour glass shaped petals 11, the hour glassshaped petals l4 and the wedge shaped petals 15. Generally the selectionof the type of screen covering that is to be used will be governed bythe type of electromagnetic radiation that is to be reflected. Inaddition, a metalized mylar sheet covering may be substituted for thewire mesh screen covering in order to permit the reflector to be used toreflect electromagnetic radiation in the infrared and visible spectrum.

A portion of the partially deployed or partially collapsed reflector 10is illustrated in FIGS. 14 and 15. As illustrated in FIG. 15 as thereflector is undergoing deployment or being collapsed the edges of thelanceolate shaped petals 11 bend inwardly elastically toward the centerof the assembly from their normal positions indicated by the appropriatebroken lines and the edges of the hour glass shaped petals l4 bendelastically outwardly and away from the center of the assembly and fromtheir normal positions indicated by the ap propriate broken lines. Itshould also be appreciated that bending of the lanceolate shaped petals11 and the hour glass shaped petals 14 can occur during certain phasesof the deployment or closing of the reflector that is reverse to thatindicated in FIG. 15. This bending of the lanceolate shaped petals 11and the hour glass shaped petals l4 permits the reflector to be readilydeployed and closed without causing any binding between the variouspetals. However, when the reflector assembly is fully deployed thelanceolate shaped petals 11 and the hour glass shaped petals 14 haveresumed their original shape and are no longer subject to elasticdeformation and thus the reflector has a rigid reflective surface.

FIG. 16 illustrates in greater detail the type of interconnecting means16 that can be utilized with this invention. The interconnecting meanscomprise a hinge member 16 that is similar in construction to thefamiliar common door hinge and comprises a left hinge member 55 and aright hinge member 56. The left hinge member 55 has an outer flange 57that has holes 58 in it for bolts or the like that can be used to attachthe flange to the edge of the appropriate petal. The flange 57 has acylindrical projection 59 that is located on its inner edge and thiscylindrical projection has a hole through it along its long axis that iscapable of accepting a pin. The right hinge member 56 also has a flange60 that has holes 61 in it for bolts or the like that can be used toattach the flange to the edge of the ap propriate petal. The flange 60has two cylindrical projections 62 located on its inner edge that areseparated to form a gap that accommodates the cylindrical projection 59.The cylindrical projections 62 have holes in them along their longcylindrical axis that accept a pin 63 that also passes through the holein the cylindrical projection 59 so that the two hinge members 55 and 56are rotatably connected to each other and are free to rotate about thepin.

In order to practice the invention, the collapsible reflector 10 isassembled in its fully deployed configuration as illustrated in FIG. 1on a suitable jig. After the reflector is assembled and tested thehydraulic unit 18 is activated and this causes the activating arms 17whose ends are pivotally connected to the lower ends of the trusses 19to push outward and upward against the trusses that are. connected tothe backs of the lanceolate shaped petals 11 and the hour glass petals14 so that the lanceolate shaped petals and the hour glass shaped petalsare pushed upward and inwardly toward the center of the assembly. Theupward and inward movement of the lanceolate shaped petals and the hourglass shaped petals also causes the wedge shaped petals 15 that arerotatably connected to the lateral edges of the lanceolate shaped petalsl1 and hour glass shaped petals 14 to begin to rotate towards each otherabout the edges of the lanceolate shaped petals as illustrated in FIG.2. As the lanceolate shaped petals 11 and the hour glass shaped petals14 move toward the center of the assembly they flex in the mannerindicated in FIG. 15 so that binding does not occur between the edges ofthe petals. As the lanceolate shaped petals l1 and the hour glass shapedpetals 14 begin to move into their final closed positions the wedgeshaped petals 15 are forced to bend backward as illustrated by thebroken lines in FIG. 10 since the lateral edges of the wedge shapedpetals are connected to the edges of the adjacent lateral edges of thehour glass petals 14 and lanceolate shaped petals l1 and the edges ofthe wedge shaped reflector are forced to conform to curvature of theedges of these lanceolate shaped and hour glass shaped petals.

If the reflector 10 is to be used in space after the reflector has beencollapsed it is then packaged in a suitable space launching vehicle andlaunched into space. When the space launch vehicle is at the desiredlocation in space the collapsible reflector 10 is ejected from thelaunch vehicle and the hydraulic unit 18 is activated to cause theactivating arms 17 to be pulled inward so that the connected trusses 19and the attached lanceolate shaped petals 11 and hour glass shapedpetals 14 are pulled outward and downward as indicated in FIG. 2. As thelanceolate shaped petals 11 and the hour glass shaped petals 14 arepulled outward and downward this causes the wedge shaped petals 15 thatare rotatably connected to the adjacent lanceolate shaped and hour glassshaped petals to rotate away from each other about the edges of thelanceolate shaped petals. As the collapsed reflector assembly 10 isundergoing deployment the wedge shaped petals 15 are pulled from theirbackward bent position illustrated in FIG. 10 to their normalconfiguration due to the shape of the lateral edges of the attachedlanceolate shaped petals l1 and hour glass shaped petals 14. It will beappreciated that as the collapsible reflector 10 is undergoingdeployment the lanceolate shaped petals 11 and the hour glass shapedpetals l4 bend from their bent positions to their normal positionsindicated in dotted lines in FIG. 15. When the lanceolate shaped petalsl1 and the hour glass shaped petals 14 have been pulled to their fullyopen positions by the action of the h draulic unit 18 the connected wedsh d t l have rotated almost about their lo rfg aif i an ihii the wedgeshaped petals, the lanceolate shaped petals and the hour glass shapedpetals provide the dished paraboloid illustrated in FIG. 1.

Although the invention has been described in considerable detail withreference to certain preferred embodiments, it will be understood thatvariations and modifications may be made within the spirit and scope ofthe invention as defined in the appended claims.

What is claimed is:

1. A collapsible and deployable reflector comprising:

a reflector hub;

a plurality of petals surrounding said reflector hub and being adaptedto present a dished substantially symetrical reflective surface upondeployment of said reflector, said petals having lateral edges that havea curvature when viewed from the focus of the deployed reflector thatsubstantially approximates the radial curvature of the surface of thepetals of the fully deployed reflector;

interconnecting means connected to the lateral adjacent edges of saidpetals for pivotally connecting said petals together in edge to edgerelationship; and

means connected to said hub and at least some of said petals forpivotally connecting said petals to said hub.

2. The collapsible and deployable reflector of claim 1 wherein saidplurality of petals comprise petals being of substantially rigidlengthwise construction and petals being of comparatively flexiblelengthwise construction alternately located between said lengthwiserigid petals.

3. The collapsible and deployable reflector of claim 2 wherein saidlengthwise rigid petals comprise substantially lanceolate shaped petalsalternating with semihour glass shaped petals.

4. The collapsible and deployable reflector of claim 2 includingreinforcing means connected to the back of each of said lengthwise rigidpetals for reinforcing said rigid petals.

5. The collapsible and deployable reflector of claim 4 wherein saidreinforcing means comprises a truss member.

6. The collapsible and deployable reflector of claim 1 including meansoperatively connected to at least some of said petals for collapsing anddeploying said petals.

7. The collapsible and deployable reflector of claim 6 wherein saidcollapsing and deploying means comprises a hydraulic activating unit.

8. The collapsible and deployable reflectorof claim 1 wherein saidpetals are adapted to present a paraboloid and the radial curvature ofthe surface of the petals of the fully deployed reflector issubstantially parabolic.

9. The collapsible and deployable reflector of claim 1 wherein saidpetals have an electromagnetically reflective wire mesh surface.

10. The collapsible and deployable reflector of claim 1 wherein saidinterconnecting means comprises hinge members.

1. A collapsible and deployable reflector comprising: a reflector hub; aplurality of petals surrounding said reflector hub and being adapted topresent a dished substantially symetrical reflective surface upondeployment of said reflector, said petals having lateral edges that havea curvature when viewed from the focus of the deployed reflector thatsubstantially approximates the radial curvature of the surface of thepetals of the fully deployed reflector; interconnecting means connectedto the lateral adjacent edges of said petals for pivotally connectingsaid petals together in edge to edge relationship; and means connectedto said hub and at least some of said petals for pivotally connectingsaid petals to said hub.
 2. The collapsible and deployable reflector ofclaim 1 wherein said plurality of petals comprise petals being ofsubstantially rigid lengthwise construction and petals being ofcomparatively flexible lengthwise construction alternately locatedbetween said lengthwise rigid petals.
 3. The collapsible and deployablereflector of claim 2 wherein said lengthwise rigid petals comprisesubstantially lanceolate shaped petals alternating with semi-hour glassshaped petals.
 4. The collapsible and deployable reflector of claim 2including reinforcing means connected to the back of each of saidlengthwise rigid petals for reinforcing said rigid petals.
 5. Thecollapsible and deployable reflector of claim 4 wherein said reinforcingmeans comprises a truss member.
 6. The collapsible and deployablereflector of claim 1 including means operatively connected to at leastsome of said petals for collapsing and deploying said petals.
 7. Thecollapsible and deployable reflector of claim 6 wherein said collapsingand deploying means comprises a hydraulic activating unit.
 8. Thecollapsible and deployable reflector of claim 1 wherein said petals areadapted to present a paraboloid and the radial curvature of the surfaceof the petals of the fully deployed reflector is substantiallyparabolic.
 9. The collapsible and deployable reflector of claim 1wherein said petals have an electromagnetically reflective wire meshsurface.
 10. The collapsible and deployable reflector of claim 1 whereinsaid interconnecting means comprises hinge members.